At least eight people have been reported missing and rescue operations are under way in the rice-farming province of Nueva Ecija where rivers burst their banks and flooded several villages, regional authorities said.

“People are asking for help because the flood waters are rising. The rescuers cannot penetrate the area as of now,” Nigel Lontoc, the assistant civil defence chief for the region, said.

Television footage showed raging brown rivers swallowing up homes and carrying off large debris including tree trunks.

A family living along the coast of Manila Bay searches for salvageable items after their house was damaged by Typhoon Koppu

The government said more than 15,000 people had already been evacuated from Koppu’s path.

Officials said more are expected to flee as the storm makes its way to the northern tip of Luzon, the Asian country’s largest island and home to about half its national population of 100 million people.

Koppu made landfall before dawn on the remote fishing town of Casiguran, whipping the coast with gusts of up to 210 kilometers (130 miles) an hour for nearly seven hours before moving inland.

“Koppu tore off roofs of homes made of light materials. Rivers overflowed, and the roads to the area are blocked by downed power pylons and trees,” Lontoc said.

A weakened Koppu later crossed over the Pantabangan dam in the southern foothills of the Cordillera, the country’s largest mountain range, with gusts of 185 kilometes an hour.

“Some villages are no longer accessible…. I was told that rescuers saw two human bodies floating in the water,” Aurelio Umali, governor of Nueva Ecija province that includes Pantabangan, told ABS-CBN.

Lontoc said the two bodies have not been recovered.

Three people in the coastal resort town of Baler, near Casiguran, are missing after a large wave struck their house, Lontoc said, and three fishermen are also missing on Manila Bay.

Flood warning

Despite the storm weakening, the authorities warned heavy rains could also trigger flash floods and landslides in the Cordillera, known for its spectacular rice terraces carved on the slopes of towering mountains.

“I must emphasise that this is just the start. People must remain alert while we try to pick up the pieces in areas already hit,” Alexander Pama, head of the National Disaster Risk Reduction Council, told reporters in Manila.

“We are strongly recommending forced evacuations in the Cordillera administrative region especially villages that are landslide- and flood-prone,” Pama said.

Lontoc, the regional disaster official, said the rain-soaked mountains also posed a threat to the heavily populated central Luzon region just north of Manila in the coming days, even though the area was spared from its winds.

With dams filling up and forced to let off water, he said huge volumes of runoff are streaming into the Pampanga river, a major waterway that spills onto the region before draining onto Manila Bay.

The weather service said Koppu would weaken further into a tropical storm by Tuesday, but continue to dump rain before heading for Taiwan on Wednesday.

Koppu caused widespread power and communications disruptions across Luzon, with many roads and bridges also blocked by landslides, floods or fallen trees and power pylons.

Thousands were stranded as ferry services were suspended amid rough seas while dozens of commercial flights were cancelled.

The Philippines suffers an average of 20 storms each year, many of them deadly.

The deadliest and strongest on record, Super Typhoon Haiyan, destroyed entire towns in the central islands in November 2013, leaving more than 7,350 people dead or missing.